1. Field of the Invention
The present invention relates to a navigation apparatus for a vehicle which determines a route to a destination, and which provides route guidance while the vehicle travels.
The present invention also relates to a navigation apparatus for a vehicle which displays a structure-profiled map so as to provide road guidance, as well as to a recording medium for use in the same.
2. Description of the Related Art
Conventionally, there has been proposed a navigation apparatus which detects the present position of a vehicle using a present position detecting unit such as a GPS sensor, and which displays a present position mark on a map based on the detected present position, thereby providing guidance.
When only the present position detecting unit is used to display the present position mark, the displayed present position mark may deviate from an actual position due to poor accuracy of detection. Thus, in order to display the present position mark on a displayed road after compensating a detection error, there has been used a technique wherein data regarding the shape of a road is stored beforehand, and the track of travel of the vehicle is compared with the stored shape of a road so as to obtain a road whose shape is most similar to the track of travel. When the detected present position deviates from the obtained road, the deviation of the present position is compensated so as to display the present position mark on the road.
In order to accurately display the present position mark through the above-described compensation processing, the present position mark is displayed on a road map in which mutually connected roads are represented by mutually connected lines, thereby providing route guidance.
In this conventional navigation apparatus, the present position can be displayed at an acceptable accuracy of display because mutually connected roads are represented by mutually connected lines. However, it is difficult for a driver to recognize the present position because the road on which the vehicle is traveling is not displayed in a distinctive manner.
In a certain navigation apparatus for a vehicle, a route to a destination is determined based on input data regarding locations such as a start point and a destination, and based on the determined route, route guidance is provided using a guidance screen and voice. This guidance screen displays a map of an area in the vicinity of the present position.
When an ordinary road map is displayed, since the types of roads such as a main road and a local road are differentiated only by use of lines having different thicknesses, the determined guidance route is displayed on the map in a distinctive manner such that a different color of display is used or a thicker line is used. When a structure-profiled map is displayed, since a road is displayed such that it has a width corresponding to an actual road width, the displayed guidance route is less likely to be recognizable. For example, in the case of a two-way road, when the same number of lanes are provided for both directions of traffic, the guidance route is displayed on the centerline of the road. Also, when a larger number of lanes are provided for traffic traveling in the opposite direction, the centerline is shifted toward the traffic side to which the vehicle belongs. As a result, the guidance route is displayed on the opposite traffic side.